Self-antigen (self-Ags) stimulation induces VISTA expression on CD4⁺ T cells and induces self-tolerance.³ Alloantigen (allo-Ags) stimulation induces transient expression of VISTA, which is lost by 24 hours and induces GVHD. Anti-VISTA mAb given during this 24-hour time window deletes alloreactive T cells via antigen-dependent cellular phagocytosis (ADCP). CD8⁺ T cells are spared, and GVL is preserved. Illustration from NIAID NIH BIOART Source (bioart.niaid.nih.gov/bioart/). Professional illustration by Patrick Lane, ScEYEnce Studios.